In this client/server world of computing that we live in today, capacity planning activity is just not limited to the server but to the entire system including the clients, servers and network devices. In the past, network capacity planners have treated the systems without serious concern and system capacity planners have in turn ignored the network devices in their analysis. One major reason for this is the lack of appropriate performance data to tie the two worlds and the fear of overhead of instrumentation.
Accuracy of model input metrics is often cited as the key indicator of the validity of a capacity analysis. In the last couple of years, there have been several papers mentioning the lack of performance data in MICROSOFT WINDOWS NT brand operating system mainly for Capacity Planning. These concerns were addressed by introducing an Event Tracing Facility in the WINDOWS NT 5.0 brand operating system and published the event tracing API. While it addressed system data requirements adequately, data related to network was lacking.
With internet access becoming common place today, there is no drop in the appetite for network bandwidth for web based applications. In fact, high speed networking is a very important focus of WINDOWS NT 5.0 brand operating system which already achieves 1 to 2 Gbps throughput. With network speeds getting this fast, any instrumentation must be highly optimized to take minimal overhead.
Most capacity planning efforts for networks have treated the system as a source generator and focused on frame counts and frame bytes by listening to the wire. Some have employed smart ways of identifying the application responsible for network traffic by scanning the packet headers. These methods are expensive and arbitrary.